auth-oauth

auth-oauth is a skill for Claude Code from qauth-labs/qauth. It costs 59 tokens per session (3,279 once invoked), scanned A, original, Apache-2.0.

A guide for implementing and reviewing OAuth 2.0 and OAuth 2.1, standards used to let applications access accounts or services without sharing passwords. It covers authorization flows, tokens, client registration, and PKCE, a code check that protects login exchanges.

In plain words
What is it for?
Use it when building or reviewing authorization-code, client-credentials, refresh-token, token, client-registration, or PKCE functionality.
Why use it?
It helps prevent insecure token handling and common mistakes in OAuth endpoints. It also provides standards-based guidance for choosing and securing different login flows.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/qauth-labs/qauth/auth-oauth
Any agent
npx skills add qauth-labs/qauth --skill auth-oauth
Clone the repo
git clone --depth 1 https://github.com/qauth-labs/qauth

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for auth-oauth

README.md
[![agentmods](https://agentmods.dev/badge/skills/qauth-labs/qauth/auth-oauth.svg)](https://agentmods.dev/skills/qauth-labs/qauth/auth-oauth)
Your own site
<a href="https://agentmods.dev/skills/qauth-labs/qauth/auth-oauth"><img src="https://agentmods.dev/badge/skills/qauth-labs/qauth/auth-oauth.svg" alt="Measured on agentmods" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,279 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00059 $0.03279
Opus 5 $0.00030 $0.01639
Sonnet 5 $0.00012 $0.00656
Haiku 4.5 $0.00006 $0.00328

Measured 6d ago against content hash 5235f2e33642, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

auth-oauth scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/auth-oauth/SKILL.md · 381 lines

How it starts

The opening of the file, as written. The whole thing — 381 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OAuth 2.0 / 2.1 (Auth)

Standards-aligned OAuth implementation and review. Follow RFC 6749 (core), RFC 9700 (security BCP, Jan 2025), RFC 7636 (PKCE), and OAuth 2.1 draft where applicable.

Standards Quick Reference

Document Purpose
RFC 6749 OAuth 2.0 Authorization Framework (core)
RFC 6750 Bearer Token Usage
RFC 7636 PKCE (Proof Key for Code Exchange)
RFC 8414 Authorization Server Metadata
RFC 9126 Pushed Authorization Requests (PAR)
RFC 9207 Authorization Server Issuer Identification
RFC 9449 DPoP (Demonstrating Proof of Possession)
RFC 9700 OAuth 2.0 Security BCP (Jan 2025)
OAuth 2.1 draft Consolidates BCP; PKCE mandatory, implicit/password grant removed

For detailed RFC/BCP excerpts and links, see reference.md.


Grant Types (What to Use / Avoid)

Grant Use? Notes
Authorization code + PKCE ✅ Required All clients (public and confidential). PKCE mandatory (RFC 9700, OAuth 2.1).
Client credentials ✅ M2M Confidential clients only. Machine-to-machine flows.
Refresh token ✅ Long-lived Bind to client; use rotation + sender-constraining.
Implicit (response_type=token) ❌ Forbidden Deprecated; tokens leak via URL/fragment/history.
Resource owner password ❌ Forbidden Exposes credentials to client (RFC 9700 §2.4).

Read the full file on GitHub · 381 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 381 lines · 59 tokens per session scan A 5235f2e33642

Subscribe to this mod's changes

auth-oauth is a skill published in the GitHub repository qauth-labs/qauth (24 stars, last pushed 5d ago), licensed Apache-2.0. It adds 59 tokens to every session and 3,279 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

update-portal-ui

Guidelines for updating or designing pages in the portal React frontend (portal/src). Covers component conventions, link rendering rules, i18n patterns, and common pitfalls.

authgear/authgear-server · 38 tokens

api-design

Review or design APIs for Authgear. In review mode, evaluates a design draft against the checklist. In ideation mode, develops a design from a description and self-reviews it.

authgear/authgear-server · 40 tokens

update-feature-config

Add or change a feature config field/section in pkg/lib/config (authgear.features.yaml). Use when adding a new feature config field, adding a new top-level section, or touching an existing section's Merge implementation.

authgear/authgear-server · 48 tokens

bootstrap-local-dev

Set up a fresh authgear-server development environment from scratch. Use when onboarding a new contributor, setting up a new machine, or when the user says "set up local dev from scratch" / "first-time setup". Covers the asdf + Homebrew install path on macOS; Nix users should follow CONTRIBUTING.md directly.

authgear/authgear-server · 71 tokens

add-go-test

Write or extend Go unit tests in this repo. Use when the user asks to add or update Go tests.

authgear/authgear-server · 26 tokens

review-pr

Produce a structured code review report for the current branch's PR (purpose, API interface changes, code quality, bugs, security, performance), with a mandatory second verification pass. Use when the user asks "what does this PR do", "review this branch/PR", or asks to confirm/double-check review findings and look…

authgear/authgear-server · 72 tokens